Nova família de modelos hidrodinâmicos reduzidos aplicados a rochas contendo falhas com múltiplas zonas de dano

• Autor(a) principal: Castro, Eduardo da Silva
• Data de Publicação: 2021
• Tipo de documento: Tese
• Idioma: por
• Título da fonte: Biblioteca Digital de Teses e Dissertações do LNCC
• Texto Completo: https://tede.lncc.br/handle/tede/345
• topic: Reservatórios; Modelos hidrodinâmicos; Fraturas (Geologia); Método dos elementos finitos; Aprendizado por computador; CNPQ::ENGENHARIAS::ENGENHARIA CIVIL::ENGENHARIA HIDRAULICA

In the context of canonical finite volume discretizations, the predictive capacity of hydrody- namic simulators in complex reservoirs, containing geological fault zones, strongly depends on the quality of the values assigned to hydraulic transmissibility multipliers, whose magnitude tends to reduce the values of intact rock due to the presence of discontinuities. In the context of two-point stencil approximations, the linear dependence with the tailings extension is commonly postulated for transmissibility, with values calculated via harmonic mean between the permeabilities of adjacent cells and that of the fault. In order to build the behavior of transmissibility multipliers in a more rigorous way, based on information from hydrodynamics at the finest scales, in this work we propose an alternative methodology to the purely macroscopic approach, built from an innovative three-scale model. Such model exhibits the ability to describe the complex microstructure of the failure zone, encompassing the nucleus and multiple adjacent damage regions, characterized by the presence of deformation bands, fractures and joints. On the finer scale of the problem, the proposed new approach describes geological structures occupying disjoint three-dimensional subdomains, and gives rise to the model called high-fidelity. In the first process of upscaling (micro-meso) we build strictly reduced models, where the fault zone is now treated as a (n − 1) dimensional (n = 2, 3) variety embedded in the matrix porous, giving rise to the presence of jumps in the fields of pressure and speed. The finite element discretization of the governing equations of the single-phase flow of the reduced model is built based on the addition of additional degrees of freedom to approximate the potential in the discontinuity. Subsequently, we proceed in the context of a flow-based upscaling process to propagate information from the reduced model to the scale of reservoir simulation cells (macroscopic). The wealth of information inherent to this procedure generates innovative constitutive laws for transmissibilities, incorporating the effects of the microstructure of the fault zone, which are commonly neglected by approaches of a purely macroscopic nature based on the approximation of two points. The methodology proposed in this work shows an enormous potential for the development of transmissibility preprocessors, more accurate to be used in commercial simulators. The information enrichment inherent to the model is illustrated in several computer simulations.